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Pools & WaterPool Chlorine Calculator — How Much Chlorine to Add?
Enter your pool’s gallons and how many ppm you want to raise free chlorine to get the liquid chlorine to add. Defaults assume 12.5% pool-grade liquid chlorine — set your product’s strength if it differs. Always follow the product label.
How this calculator works
About 10.7 fl oz of 12.5% liquid chlorine raises 10,000 gallons by 1 ppm free chlorine; we scale that by your gallons, target ppm, and product strength. Granular (cal-hypo) and tablets differ — this is for liquid chlorine or bleach.
What changes how much you need
- To “shock,” many raise free chlorine to about 10 ppm — or follow your shock product’s label.
- Household bleach is usually ~6%, half the strength of pool chlorine — set the strength field and it’ll need about double the volume.
- Add chlorine in the evening with the pump running; sun burns off unstabilized chlorine fast.
- Start conservative and retest — it’s far easier to add more than to remove it.
Frequently asked questions
How much liquid chlorine to add to a pool?
About 10.7 fl oz of 12.5% liquid chlorine raises 10,000 gallons by 1 ppm free chlorine. A 15,000-gallon pool up 3 ppm needs roughly 48 fl oz. Enter your numbers above.
Can I use bleach instead of pool chlorine?
Yes — household bleach is ~6% vs pool chlorine’s ~12.5%, so set the strength to 6 and expect about double the volume.
How much chlorine to shock a pool?
Shocking usually means raising free chlorine to about 10 ppm (or per your shock product). Set “raise free chlorine by” to reach that from your current level, and follow the label.